Patent GB-190316113-A (GB)
Title: Improved Mode of and Apparatus for Producing and Detecting Hertzian Oscillations.
Inventor: MASKELYNE JOHN NEVIL
Filed: 1903-07-21
Granted: 1904-07-14
Abstract: 16,113. Maskelyne, J. N. July 21. Telegraphs.-In a system of wireless signalling in which Hertzian oscillations are employed, the aÙrial conductor consists of a loop j of wire vertically supported from its central point by a mast &c. The transmitting-key k<1> is pivoted at h to a pivoted arm q, which is joined by a vulcanite connecting-rod u to a lever controlling a rotary switch l. A spring w normally holds the key k<1> in the inoperative position and causes the switch l to connect the ends of the loop j to earth at 1, 2 and to the receiving-apparatus at 6, 7. When the key is moved into the operative position, for signalling, the switch l makes contact at 1, 8 and 6, 5, thus connecting the transmitting-apparatus to the loop j. Contact is also made at 4, 3 for a purpose explained below. The wave-detector or "con- " junctor is shown in Fig. 5. It comprises a glass tube c, on the ends of which metal caps 9 are cemented. Through these caps are passed plugs 10 with ends ground truly spherical and brought to a mirror polish. The space between the spherical surfaces is bridged by a hollow cylinder 11, the ends of which are bevelled and accurately ground to a knife edge, and polished. The plugs and cylinder are preferably of hardened steel, which has been heated sufficiently to cause the formation of a pale yellow film of oxide on the surface. One of the plugs is provided with a cavity z for containing a small quantity of calcium chloride or other drying agent. The cylinder may have spherical ends fitting into knife-edged cups. The receiving-apparatus includes a condenser n, adjustable inductance i, and "conjunctor" c. The inductance i consists of uninsulated copper wire wound on an insulating-cylinder and provided with a short-circuiting slider. The combination of condenser and inductance is adapted for tuning purposes, and is designated an "integrator." The condenser is shunted by a relay r, a fraction of the potential of the cell b being introduced into the circuit. When contact is made at the "conjunctor," current passes through the circuit, which includes the inductance i, relay r, loop j, and earth. The relay r closes the circuit of a battery b<2> through an electromagnet d and contact v, d<1>, Figs. 1 and 6. The conjunctor c is supported by the armature d*, which thus serves as a decoherer. The armature also effects the rocking of the arm v so as to break contact at d' and make momentary contact at m<1>, thus closing the circuit of a battery b<3> through the Morse recording- instrument m. The movements of the arm v are very rapid when a stream of impulses is being received, the ink-wheel of the Morse instrument failing to leave the paper, and tracing a long or a short line thereon according to the period during which the impulses are received. The transmitting-apparatus includes an induction coil t with interrupter f, condenser n<1>, and spark gap g. During transmission, an electromagnet o is energized owing to the contact at 3, 4. Two contact arms c', carried on a rock-shaft, are thus moved into the position shown in dotted lines in Fig. 6, the conjunctor being then entirely disconnected from the receiving-circuit and protected against any possibility of injury. Condensers may be inserted in the loop j, and an adjustable inductance may be inserted between its ends. Other adjustable inductances may be placed in circuit with the condensers in the loop. A motordriven commutator may be used as the interrupter of the induction coil.